net: systemport: Use eth_hw_addr_random

Use eth_hw_addr_random() instead of calling random_ether_addr().
Here, this change is setting addr_assign_type to NET_ADDR_RANDOM.

The Coccinelle semantic patch that performs this transformation
is as follows:

@@
identifier a,b;
@@

-random_ether_addr(a->b);
+eth_hw_addr_random(a);

Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>